This instrument was a remote electromechanical musical instrument using telegraphy and electric buzzers which can generate fixed timbre sound. Though it lacked an arbitrary sound-synthesis function, some have erroneously called it the first synthesizer.[1][2]

In 1906, American engineer, Lee De Forest ushered in the "electronics age".[6] He invented the first amplifyingvacuum tube, called the Audion tube. This led to new entertainment technologies, including radio and sound films. These new technologies also influenced the music industry, and resulted in various early electronic musical instruments that used vacuum tubes, including:

Most of these early instruments used "heterodyne circuits" to produce audio frequencies, and were limited in their synthesis capabilities. Ondes Martenot and Trautonium were continuously developed for several decades, finally developing qualities similar to later synthesizers.

Solovox (1940) by Hammond Organ Company — a monophonic attachment keyboard instrument consisting of a large tone-cabinet and a small keyboard-unit, intended to accompany the pianos with lead voice of organ and orchestral sound.

However, at least one Japanese was not satisfied the situation at that time. In 1949, Japanese composer Minao Shibata discussed the concept of "a musical instrument with very high performance" that can "synthesize any kind of sound waves" and is "...operated very easily," predicting that with such an instrument, "...the music scene will be changed drastically."[neutrality is disputed][20][21]

After World War II, electronic music including electroacoustic music and musique concrète was created by contemporary composers, and numerous electronic music studios were established around the world, especially in Bonn, Cologne, Paris and Milan. These studios were typically filled with electronic equipment including oscillators, filters, tape recorders, audio consoles etc., and the whole studio functioned as a "sound synthesizer".

In 1959–1960, Harald Bode developed a modular synthesizer and sound processor,[25][26] and in 1961, he wrote a paper exploring the concept of self-contained portable modular synthesizer using newly emerging transistor technology.[27] He also served as AES session chairman on music and electronic for the fall conventions in 1962 and 1964.[28] His ideas were adopted by Donald Buchla and Robert Moog in the United States, and Paul Knetoff in Italy[29][30][31] at about the same time:[32] among them, Moog is known as the first synthesizer designer to popularize the voltage control technique in analog electronic musical instruments.[32]

Robert Moog built his first prototype between 1963-1964, and was then commissioned by the Alwin Nikolais Dance Theater of NY;[33][34] while Donald Buchla was commissioned by Morton Subotnick.[35][36] In the late 1960s to 1970s, the development of miniaturized solid-state components allowed synthesizers to become self-contained, portable instruments, as proposed by Harald Bode in 1961. By the early 1980s, companies were selling compact, modestly priced synthesizers to the public. This, along with the development of Musical Instrument Digital Interface (MIDI), made it easier to integrate and synchronize synthesizers and other electronic instruments for use in musical composition. In the 1990s, synthesizer emulations began to appear in computer software, known as software synthesizers. Later, VST and other plugins were able to emulate classic hardware synthesizers to a moderate degree.

In 1978, the success of the Prophet 5, a polyphonic and microprocessor-controlled keyboard synthesizer, strongly aided the shift of synthesizers towards their familiar modern shape, away from large modular units and towards smaller keyboard instruments.[45] This form factor helped accelerate the integration of synthesizers into popular music, a shift that had been lent powerful momentum by the Minimoog, and also later the ARPOdyssey.[46] Earlier polyphonic electronic instruments of the 1970s, rooted in string synthesizers before advancing to multi-synthesizers incorporating monosynths and more, gradually fell out of fashion in the wake of these newer, note-assigned polyphonic keyboard synthesizers.[47] These polyphonic synthesizers were mainly manufactured in the United States and Japan from the mid-1970s to the early-1980s, and included the Yamaha CS-80 (1976), Oberheim's Polyphonic and OBX (1975 and 1979), Sequential Circuits' Prophet-5 (1978), and Roland's Jupiter 4 and Jupiter 8 (1978 and 1981).

By the end of the 1970s, digital synthesizers and digital samplers arrived on the market around the world (and are still sold today),[note 1] as the result of preceding research and development.[note 1] Compared with analog synthesizer sounds, the digital sounds produced by these new instruments tended to have a number of different characteristics: clear attack and sound outlines, carrying sounds, rich overtones with inharmonic contents, and complex motion of sound textures, amongst others. While these new instruments were expensive, these characteristics meant musicians were quick to adopt them, especially in the United Kingdom[48] and the United States. This encouraged a trend towards producing music using digital sounds,[note 2] and laid the foundations for the development of the inexpensive digital instruments popular in the next decade (see below). Relatively successful instruments with each selling more than several hundred units per series, included the NEDSynclavier (1977), Fairlight CMI (1979), E-mu Emulator (1981), and PPG Wave (1981).[note 1][48][49][50][51]

Throughout the 1990s, the popularity of electronic dance music employing analog sounds, the appearance of digital analog modelling synthesizers to recreate these sounds, and the development of the Eurorack modular synthesiser system, initially introduced with the Doepfer A-100 and since adopted by other manufacturers, all contributed to the resurgence of interest in analog technology. The turn of the century also saw improvements in technology that led to the popularity of digital software synthesizers.[56] In the 2010s, new analog synthesizers, both in keyboard instrument and modular form, are released alongside current digital hardware instruments.[57]

Additive synthesis builds sounds by adding together waveforms (which are usually harmonically related). Early analog examples of additive synthesizers are the Teleharmonium and Hammond organ. To implement real-time additive synthesis, wavetable synthesis is useful for reducing required hardware/processing power,[63] and is commonly used in low-end MIDI instruments (such as educational keyboards) and low-end sound cards.

Subtractive synthesis is based on filtering harmonically rich waveforms. Due to its simplicity, it is the basis of early synthesizers such as the Moog synthesizer. Subtractive synthesizers use a simple acoustic model that assumes an instrument can be approximated by a simple signal generator (producing sawtooth waves, square waves, etc.) followed by a filter. The combination of simple modulation routings (such as pulse width modulation and oscillator sync), along with the physically unrealistic lowpass filters, is responsible for the "classic synthesizer" sound commonly associated with "analog synthesis"—a term which is often mistakenly used when referring to software synthesizers using subtractive synthesis.

FM synthesis (frequency modulation synthesis) is a process that usually involves the use of at least two signal generators (sine-wave oscillators, commonly referred to as "operators" in FM-only synthesizers) to create and modify a voice. Often, this is done through the analog or digital generation of a signal that modulates the tonal and amplitude characteristics of a base carrier signal. FM synthesis was pioneered by John Chowning, who patented the idea and sold it to Yamaha. Unlike the exponential relationship between voltage-in-to-frequency-out and multiple waveforms in classical 1-volt-per-octave synthesizer oscillators, Chowning-style FM synthesis uses a linear voltage-in-to-frequency-out relationship and sine-wave oscillators. The resulting complex waveform may have many component frequencies, and there is no requirement that they all bear a harmonic relationship. Sophisticated FM synths such as the Yamaha DX-7 series can have 6 operators per voice; some synths with FM can also often use filters and variable amplifier types to alter the signal's characteristics into a sonic voice that either roughly imitates acoustic instruments or creates sounds that are unique. FM synthesis is especially valuable for metallic or clangorous noises such as bells, cymbals, or other percussion.

Physical modelling synthesis is the synthesis of sound by using a set of equations and algorithms to simulate a real instrument, or some other physical source of sound. This involves modelling components of musical objects and creating systems that define action, filters, envelopes and other parameters over time. Various models can also be combined, e.g. the model of a violin with characteristics of a pedal steel guitar and the action of piano hammer. When an initial set of parameters is run through the physical simulation, the simulated sound is generated. Although physical modeling was not a new concept in acoustics and synthesis, it was not until the development of the Karplus-Strong algorithm and the increase in DSP power in the late 1980s that commercial implementations became feasible. The quality and speed of physical modeling on computers improves with higher processing power.

Sample-based synthesis involves recording a real instrument as a digitized waveform, and then playing back its recordings at different speeds (pitches) to produce different tones. This technique is referred to a "sampling". Most samplers designate a part of the sample for each component of the ADSR envelope, repeating that section while changing the volume according to the envelope. This allows samplers to vary the envelope while playing the same note. See also Wavetable synthesis, Vector synthesis.

Analysis/resynthesis is a form of synthesis that uses a series of bandpass filters or Fourier transforms to analyze the harmonic content of a sound. The results are then used to resynthesize the sound using a band of oscillators. The vocoder, linear predictive coding, and some forms of speech synthesis are based on analysis/resynthesis.

Sound synthesis can be used to mimic acoustic sound sources. Generally, a sound that does not change over time includes a fundamental partial or harmonic, and any number of partials. Synthesis may attempt to mimic the amplitude and pitch of the partials in an acoustic sound source.

When natural sounds are analyzed in the frequency domain (as on a spectrum analyzer), the spectra of their sounds exhibits amplitude spikes at each of the fundamental tone's harmonics corresponding to resonant properties of the instruments (spectral peaks that are also referred to as formants). Some harmonics may have higher amplitudes than others. The specific set of harmonic-vs-amplitude pairs is known as a sound's harmonic content. A synthesized sound requires accurate reproduction of the original sound in both the frequency domain and the time domain. A sound does not necessarily have the same harmonic content throughout the duration of the sound. Typically, high-frequency harmonics die out more quickly than the lower harmonics.

In most conventional synthesizers, for purposes of re-synthesis, recordings of real instruments are composed of several components representing the acoustic responses of different parts of the instrument, the sounds produced by the instrument during different parts of a performance, or the behavior of the instrument under different playing conditions (pitch, intensity of playing, fingering, etc.)

Synthesizers generate sound through various analogue and digital techniques. Early synthesizers were analog hardware based but many modern synthesizers use a combination of DSP software and hardware or else are purely software-based (see softsynth). Digital synthesizers often emulate classic analog designs. Sound is controllable by the operator by means of circuits or virtual stages that may include:

Electronic oscillators – create raw sounds with a timbre that depends upon the waveform generated. Voltage-controlled oscillators (VCOs) and digital oscillators may be used. Harmonic additive synthesis models sounds directly from pure sine waves, somewhat in the manner of an organ, while frequency modulation and phase distortion synthesis use one oscillator to modulate another. Subtractive synthesis depends upon filtering a harmonically rich oscillator waveform. Sample-based and granular synthesis use one or more digitally recorded sounds in place of an oscillator.

Voltage-controlled filter (VCF) – "shape" the sound generated by the oscillators in the frequency domain, often under the control of an envelope or LFO. These are essential to subtractive synthesis.

Voltage-controlled amplifier (VCA) – After the signal generated by one (or a mix of more) VCOs has been modified by filters and LFOs, and its waveform has been shaped (contoured) by an ADSR envelope generator, it then passes on to one or more voltage-controlled amplifiers (VCAs). A VCA is a preamp that boosts (amplifies) the electronic signal before passing it on to an external or built-in power amplifier, as well as a means to control its amplitude (volume) using an attenuator. The gain of the VCA is affected by a control voltage (CV), coming from an envelope generator, an LFO, the keyboard or some other source.[64]

ADSR envelopes – provide envelope modulation to "shape" the volume or harmonic content of the produced note in the time domain with the principle parameters being attack, decay, sustain and release. These are used in most forms of synthesis. ADSR control is provided by envelope generators.

Low frequency oscillator (LFO) – an oscillator of adjustable frequency that can be used to modulate the sound rhythmically, for example to create tremolo or vibrato or to control a filter's operating frequency. LFOs are used in most forms of synthesis.

The filter may be controlled with a second ADSR envelope. An "envelope modulation" ("env mod") parameter on many synthesizers with filter envelopes determines how much the envelope affects the filter. If turned all the way down, the filter producs a flat sound with no envelope. When turned up the envelope becomes more noticeable, expanding the minimum and maximum range of the filter.

When an acoustic musical instrument produces sound, the loudness and spectral content of the sound change over time in ways that vary from instrument to instrument. The "attack" and "decay" of a sound have a great effect on the instrument's sonic character.[65] Sound synthesis techniques often employ an envelope generator that controls a sound's parameters at any point in its duration. Most often this is an "ADSR" (Attack Decay Sustain Release) envelope, which may be applied to overall amplitude control, filter frequency, etc. The envelope may be a discrete circuit or module, or implemented in software. The contour of an ADSR envelope is specified using four parameters:

Attack time is the time taken for initial run-up of level from nil to peak, beginning when the key is first pressed.

Decay time is the time taken for the subsequent run down from the attack level to the designated sustain level.

Sustain level is the level during the main sequence of the sound's duration, until the key is released.

Release time is the time taken for the level to decay from the sustain level to zero after the key is released.

An early implementation of ADSR can be found on the Hammond Novachord in 1938 (which predates the first Moog synthesizer by over 25 years). A seven-position rotary knob set preset ADS parameter for all 72 notes; a pedal controlled release time.[15] The notion of ADSR was specified by Vladimir Ussachevsky (then head of the Columbia-Princeton Electronic Music Center) in 1965 while suggesting improvements for Bob Moog's pioneering work on synthesizers, although the earlier notations of parameter were (T1, T2, Esus, T3), then these were simplified to current form (Attack time, Decay time, Sustain level, Release time) by ARP.[66]

Some electronic musical instruments allow the ADSR envelope to be inverted, which results in opposite behavior compared to the normal ADSR envelope. During the attack phase, the modulated sound parameter fades from the maximum amplitude to zero then, during the decay phase, rises to the value specified by the sustain parameter. After the key has been released the sound parameter rises from sustain amplitude back to maximum amplitude.

A common variation of the ADSR on some synthesizers, such as the Korg MS-20, was ADSHR (attack, decay, sustain, hold, release). By adding a "hold" parameter, the system allowed notes to be held at the sustain level for a fixed length of time before decaying. The General Instruments AY-3-8912sound chip included a hold time parameter only; the sustain level was not programmable. Another common variation in the same vein is the AHDSR (attack, hold, decay, sustain, release) envelope, in which the "hold" parameter controls how long the envelope stays at full volume before entering the decay phase. Multiple attack, decay and release settings may be found on more sophisticated models.

Certain synthesizers also allow for a delay parameter before the attack. Modern synthesizers like the Dave Smith InstrumentsProphet '08 have DADSR (delay, attack, decay, sustain, release) envelopes. The delay setting determines the length of silence between hitting a note and the attack. Some software synthesizers, such as Image-Line's 3xOSC (included with their DAWFL Studio) have DAHDSR (delay, attack, hold, decay, sustain, release) envelopes.

A low-frequency oscillator (LFO) generates an electronic signal, usually below 20 Hz. LFO signals create a periodic control signal or sweep, often used in vibrato, tremolo and other effects. In certain genres of electronic music, the LFO signal can control the cutoff frequency of a VCF to make a rhythmic wah-wah sound, or the signature dubstepwobble bass.

A synthesizer patch (some manufacturers chose the term program) is a sound setting. Modular synthesizers used cables ("patch cords") to connect the different sound modules together. Since these machines had no memory to save settings, musicians wrote down the locations of the patch cables and knob positions on a "patch sheet" (which usually showed a diagram of the synthesizer). Ever since, an overall sound setting for any type of synthesizer has been referred to as a patch.

In mid–late 1970s, patch memory (allowing storage and loading of 'patches' or 'programs') began to appear in synths like the Oberheim Four-voice (1975/1976)[67] and Sequential Circuits Prophet-5 (1977/1978). After MIDI was introduced in 1983, more and more synthesizers could import or export patches via MIDI SYSEX commands. When a synthesizer patch is uploaded to a personal computer that has patch editing software installed, the user can alter the parameters of the patch and download it back to the synthesizer. Because there is no standard patch language it is rare that a patch generated on one synthesizer can be used on a different model. However sometimes manufacturers design a family of synthesizers to be compatible.

Modern synthesizers often look like small pianos, though with many additional knob and button controls. These are integrated controllers, where the sound synthesis electronics are integrated into the same package as the controller. However, many early synthesizers were modular and keyboardless, while most modern synthesizers may be controlled via MIDI, allowing other means of playing such as:

Rock musician Keith Emerson used it with the Moog modular synthesizer from 1970 onward. In the late 1980s, keyboards in the synth lab at Berklee College of Music were equipped with membrane thin ribbon style controllers that output MIDI. They functioned as MIDI managers, with their programming language printed on their surface, and as expression/performance tools. Designed by Jeff Tripp of Perfect Fretworks Co., they were known as Tripp Strips. Such ribbon controllers can serve as a main MIDI controller instead of a keyboard, as with the Continuum instrument.

Wind controllers (and wind synthesizers) are convenient for woodwind and brass players, being designed to imitate those instruments. These are usually either analog or MIDI controllers, and sometimes include their own built-in sound modules (synthesizers). In addition to the follow of key arrangements and fingering, the controllers have breath-operated pressure transducers, and may have gate extractors, velocity sensors, and bite sensors. Saxophone style controllers have included the Lyricon, and products by Yamaha, Akai, and Casio. The mouthpieces range from alto clarinet to alto saxophone sizes. The Eigenharp, a controller similar in style to a bassoon, was release by Eigenlabs in 2009. Melodica and recorder style controllers have included the Martinetta (1975)[78] and Variophon (1980),[79] and Joseph Zawinul's custom KorgPepe.[80] A Harmonica style interface was the Millionizer 2000 (c.1983).[81]

Other controllers include: Theremin, lightbeam controllers, touch buttons (touche d’intensité) on the Ondes Martenot, and various types of foot pedals. Envelope following systems, the most sophisticated being the vocoder, are controlled by the power or amplitude of input audio signal. The Talk box allows sound to be manipulated using the vocal tract, although it is rarely categorized as a synthesizer.

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Kirk Pearson's "A Man Who Went Missing" utilizes MIDI samplers to produce effects that would be difficult or even impossible for their acoustic counterparts.

Synthesizers became easier to integrate and synchronize with other electronic instruments and controllers with the introduction of Musical Instrument Digital Interface (MIDI) in 1983.[84] First proposed in 1981 by engineer Dave Smith of Sequential Circuits, the MIDI standard was developed by a consortium now known as the MIDI Manufacturers Association.[85] MIDI is an opto-isolatedserial interface and communication protocol.[85] It provides for the transmission from one device or instrument to another of real-time performance data. This data includes note events, commands for the selection of instrument presets (i.e. sounds, or programs or patches, previously stored in the instrument's memory), the control of performance-related parameters such as volume, effects levels and the like, as well as synchronization, transport control and other types of data. MIDI interfaces are now almost ubiquitous on music equipment and are commonly available on personal computers (PCs).[85]

The General MIDI (GM) software standard was devised in 1991 to serve as a consistent way of describing a set of over 200 sounds (including percussion) available to a PC for playback of musical scores.[86] For the first time, a given MIDI preset consistently produced a specific instrumental sound on any GM-compatible device. The Standard MIDI File (SMF) format (extension.mid) combined MIDI events with delta times – a form of time-stamping – and became a popular standard for exchanging music scores between computers. In the case of SMF playback using integrated synthesizers (as in computers and cell phones), the hardware component of the MIDI interface design is often unneeded.

Open Sound Control (OSC) is another music data specification designed for online networking. In contrast with MIDI, OSC allows thousands of synthesizers or computers to share music performance data over the Internet in realtime.

In popular music, a synth lead is generally used for playing the main melody of a song, but it is also often used for creating rhythmic or bass effects. Although most commonly heard in electronic dance music, synth leads have been used extensively in hip-hop since the 1980s and rock songs since the 1970s. Most modern music relies heavily on the synth lead to provide a musical hook to sustain the listener's interest throughout an entire song.

A synth pad is a sustained chord or tone generated by a synthesizer, often employed for background harmony and atmosphere in much the same fashion that a string section is often used in acoustic music. Typically, a synth pad plays many whole or half notes, sometimes holding the same note while a lead voice sings or plays an entire musical phrase. Often, the sounds used for synth pads have a vaguely organ, string, or vocal timbre. Much popular music in the 1980s employed synth pads, this being the time of polyphonic synthesizers, as did the then-new styles of smooth jazz and New Age music. One of many well-known songs from the era to incorporate a synth pad is "West End Girls" by the Pet Shop Boys, who were noted users of the technique.

The main feature of a synth pad is very long attack and decay time with extended sustains. In some instances pulse-width modulation (PWM) using a square wave oscillator can be added to create a "vibrating" sound.

The bass synthesizer (or "bass synth") is used to create sounds in the bass range, from simulations of the electric bass or double bass to distorted, buzz-saw-like artificial bass sounds, by generating and combining signals of different frequencies. Bass synth patches may incorporate a range of sounds and tones, including wavetable-style, analog, and FM-style bass sounds, delay effects, distortion effects, envelope filters. A modern digital synthesizer uses a frequency synthesizermicroprocessor component to generate signals of different frequencies. While most bass synths are controlled by electronic keyboards or pedalboards, some performers use an electric bass with MIDI pickups to trigger a bass synthesizer.

In the 1970s miniaturized solid-state components allowed self-contained, portable instruments such as the Moog Taurus, a 13-note pedal keyboard played by the feet. The Moog Taurus was used in live performances by a range of pop, rock, and blues-rock bands. An early use of bass synthesizer was in 1972, on a solo album by John Entwistle (the bassist for The Who), entitled Whistle Rymes. Genesis bass player Mike Rutherford used a Dewtron "Mister Bassman" for the recording of their album Nursery Cryme in August 1971. Stevie Wonder introduced synth bass to a pop audience in the early 1970s, notably on "Superstition" (1972) and "Boogie On Reggae Woman" (1974). In 1977 Parliament's funk single "Flash Light" used the bass synthesizer. Lou Reed, widely considered a pioneer of electric guitar textures, played bass synthesizer on the song "Families", from his 1979 album The Bells.

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An example of acid bass track, using SH-101 for bass, MC-202 for filter hookline, and TR-808 for drums.

When the programmable music sequencer became widely available in the 1980s (e.g., the Synclavier), bass synths were used to create highly syncopated rhythms and complex, rapid basslines. Bass synth patches incorporate a range of sounds and tones, including wavetable-style, analog, and FM-style bass sounds, delay effects, distortion effects, envelope filters. A particularly influential bass synthesizer was the Roland TB-303 following Firstman SQ-01. Released in late 1981, it featured a built-in sequencer and later became strongly associated with acid house music. This method gained wide popularity after Phuture used it for the single "Acid Tracks" in 1987.[88]

In the 2000s, several equipment manufacturers such as Boss and Akai produced bass synthesizer effect pedals for electric bass guitar players, which simulate the sound of an analog or digital bass synth. With these devices, a bass guitar is used to generate synth bass sounds. The BOSS SYB-3 was one of the early bass synthesizer pedals. The SYB-3 reproduces sounds of analog synthesizers with Digital Signal Processing saw, square, and pulse synth waves and user-adjustable filter cutoff. The Akai bass synth pedal contains a four-oscillator synthesizer with user selectable parameters (attack, decay, envelope depth, dynamics, cutoff, resonance). Bass synthesizer software allows performers to use MIDI to integrate the bass sounds with other synthesizers or drum machines. Bass synthesizers often provide samples from vintage 1970s and 1980s bass synths. Some bass synths are built into an organ style pedalboard or button board.

An arpeggiator is a feature available on several synthesizers that automatically steps through a sequence of notes based on an input chord, thus creating an arpeggio. The notes can often be transmitted to a MIDI sequencer for recording and further editing. An arpeggiator may have controls for speed, range, and order in which the notes play; upwards, downwards, or in a random order. More advanced arpeggiators allow the user to step through a pre-programmed complex sequence of notes, or play several arpeggios at once. Some allow a pattern sustained after releasing keys: in this way, sequence of arpeggio patterns may be built up over time by pressing several keys one after the other. Arpeggiators are also commonly found in software sequencers. Some arpeggiators/sequencers expand features into a full phrase sequencer, which allows the user to trigger complex, multi-track blocks of sequenced data from a keyboard or input device, typically synchronized with the tempo of the master clock.

^Kreichi, Stanislav (10 November 1997), The ANS Synthesizer: Composing on a Photoelectronic Instrument, Theremin Center, Despite the apparent simplicity of his idea of reconstructing a sound from its visible image, the technical realization of the ANS as a musical instrument did not occur until 20 years later. / Murzin was an engineer who worked in areas unrelated to music, and the development of the ANS synthesizer was a hobby and he had many problems realizing on a practical level.

^Vail 2000, p. 71, The Euro-Synth Industry - Italy. "First things first: In 1964, Paul Ketoff constructed the Synket in Rome. This was around the time that Bob Moog and Don Buchla independently began shipping their modular synthesizer wares."

^ abHolmes 2008, p. 208. "Moog became the first synthesizer designer to popularize the technique of voltage control in analog electronic musical instruments. Donald Buchla in the United States and Paul Ketoff in Italy had been developing commercial synthesizers using the same principle at about the same time, but their equipment never reached the level of public acceptance of Moog's products and only a handful were sold."

^Gluck, Bob (October 16, 2013), "Morton Subotnick’s Sidewinder", New Music USA, When Subotnick (with Ramon Sender) commissioned Donald Buchla to design what became the Buchla Box, his goal was an artist-friendly compositional tool that didn’t depend upon recorded sound. ... The process of its development by Don Buchla, initially a spinning light wheel to create waveforms and then a modular system with integrated circuits, is described in the Spring 2012 issue of Computer Music Journal. ... The Buchla prototype was ready for the 1964-1965 season, but was little used prior to Subotnick’s departure for New York in 1966. His theater piece Play 4 (1966) was the only work for the Buchla that Subotnick completed in San Francisco.

^ abLeete, Norm. "Fairlight Computer". Sound On Sound (April 1999). The huge cost of the Fairlight CMI did not put the rich and famous off. Peter Vogel brought an early CMI to the UK in person, and one of the first people to get one was Peter Gabriel. Once UK distributor Syco Systems had been set up, the client list started to grow. ... as the total number of CMIs and Series II / IIxs comes to about 300 (of which only about 50 made it to the UK). (Note: CMI III seems not in count)

^"Radio Squeals Turned to Music for Entire Orchestra", Popular Science (June 1932): 51
— the article reported Léon Theremin's new electronic instruments used on his electric orchestra's first public recital at Carnegie Hall, New York City, including Fingerboard Theremin, Keyboard Theremin with fingerboard controller, and Terpsitone (a performance instrument in the style of platform on which a dancer could play a music by the movement of body).